The present invention relates to an imprint technique (a so-called nano-imprint technique) in which a resin disposed on a substrate and a mold are pressed to each other to form a resin pattern on the substrate.
The nano-imprinting technique enables transferring of even a microscopic pattern of about 10 nm, which is used for manufacturing various devices including a semiconductor chip such as an IC or a LSI, a display element such as a liquid crystal panel, a detection element such as a magnetic head, and an image pickup element such as a CCD (refer to p. 85 to 87, Science, vol. 272, by S. Y. Chou, et. Al., Apr. 5, 1996).
The nano-imprinting technique includes a thermal cycle method and an optical curing (UV curing) method. The thermal cycle method heats a resin (thermoplastic resin) to a glass transition temperature or more to increase fluidity of the resin, and releases the mold from the resin after cooling in a pressed state of the mold to the resin. The optical curing method irradiates an ultraviolet (UV)-curable resin with ultraviolet (UV) light through a transparent mold in a pressed state of the mold to the UV-curable resin to cure the UV-curable resin, and then releases the mold from the cured resin.
Such a nano-imprinting technique is desired to take a shorter time for a mold pressing (stamping) step. Japanese Patent Laid-Open No. 2004-288811 discloses a technique for increasing fluidity of a resin by ultrasonically vibrating a mold to lower viscosity of the resin when the mold is pressed to the resin, and facilitating spreading of the resin to even microscopic concave portions of a pattern within a short time.
Further, in the mold pressing step, a load applied on the mold (that is, a pressing force applied between the mold and the resin) has to be maintained constant. This is because dimensional accuracy of a pattern transferred to the resin is reduced when the load varies. In Japanese Patent Laid-Open No. 2004-288811, however, there is no mention of such load control.
The mold pressing step is subdivided into a step of moving one of the mold and the resin close to the other from a position where the mold is separated from the resin to a position where they come into contact with each other, and a step of controlling a load of pressing the mold to the resin to be constant.
To quicken the mold pressing step, if a moving speed of the mold or the resin (substrate) is simply increased in the former step, a large shock is generated at a moment when the mold comes into contact with the resin. Even in a case where the mold and the resin are brought into contact with each other in parallel, if viewed microscopically, an apex of one of the mold and the resin comes into point-contact with the other, which may cause destruction of the mold by the shock.
Moreover, in the nano-imprinting by the UV-curing method, the mold is made of glass such as quartz which transmits UV light, and vulnerable to shocks. Thus, in the mold pressing step, the mold has to be slowly brought close to the resin, which increases the time necessary for the mold pressing step.